Alvarinho Luis
Climate change has brought in a host of environmental problems such as droughts and heat waves, which are occurring simultaneously with much greater frequency than in the past. According to published research in Scientific Reports by climate experts at the University of California, hot weather’s most deadly effects for humans comes from a combination of high temperature and high humidity.
Heat waves were defined as three or more consecutive hot days in the historical record. Amplified by high humidity, the temperature can reach above 40 degrees Celsius, causing severe direct and indirect damage to the environment on spatial and temporal scales, with impacts on human health, air quality, and vegetation.
Because humid air retains more heat, it prevents the human body from cooling down through sweating leading to hyperthermia which causes physiological stress. Because the normal human body core, which includes the brain, lungs and other organs, functions within a very narrow limit of temperature of ±1 degree Celsius, disruption of the body’s ability to regulate temperature can immediately impair physical and cognitive functions.
With a positive global-warming trend, more people are exposed to heat strokes, especially in densely populated and poverty-ridden Asian countries. For example, severe heat waves caused mortality to humans and livestock in Odisha in 1998, AP in 2003, and parts of Gujarat in 2010. The fifth deadliest heat wave in recorded history claimed around 3500 lives in India and Pakistan in 2015. In 2017, heat wave (nicknamed Lucifer) with temperature exceeding 40 degrees Celsius swept across urban areas in Chicago, Shanghai and Europe leading to many deaths, power grid failure, and dehydration-related illnesses.
So what causes the air temperature to rise? Human-caused climate change drives more extreme summer heat waves as a result of increased pumping of carbon dioxide, water vapor, and other greenhouse gases (GHG) into the atmosphere. In India and China emission rates of GHG continue to rise, driven mostly by economic and population growth and high dependence on fossil fuel (petrol, diesel and coal) for energy generation, transport vehicles and factories. The GHG prevents heat radiation from leaving the atmosphere, thereby increasing the surface temperature (global warming). Enhanced evaporation due to surface warming pushes humidity levels higher, resulting in heat waves during warm season.
Will smart cities exacerbate heat waves? Smart Cities Mission will generate 63% of the country’s GDP by developing infrastructural facilities like roads, buildings, residential apartments, malls, etc, possibly by sacrificing vegetated areas and natural surfaces. The heat-trapping concrete and asphalt and heat released from cars radiators and air conditioners will result in urban heat island. Globally, this effect is expected to add a further two degrees to global warming estimates for the most populated cities by 2050, which will boast up heat wave intensity.
